Life cycle assessment of rainwater harvesting systems for Brazilian semi‐arid households

Rainwater harvesting (RWH) is increasingly utilized today by populations to alleviate water supply issues, particularly in rural, dry environments. Limited research has considered, simultaneously, the numerous factors that contribute to sustainability – for example, social acceptance, water quality, and maintenance needs – of RWH. This research aimed to improve the understanding of factors influencing the sustainability of rainwater harvesting systems for domestic use (DRWHS) through examination of social, water quality, and technical feasibility components. We conducted 50 household surveys and 17 rainwater quality analyses in San Jose Xacxamayo, a rural, semi-arid community in Puebla, Mexico. Results showed that DRWHS are socially accepted primarily because of the presence of existing local skills and knowledge, as well as critical need for water. Results from most of the water quality parameters measured were within World Health Organization (WHO) guidelines for human consumption, with the exception of pH, total coliform, and heterotrophic plate count, which required water treatment prior to consumption. Technical feasibility was the main barrier to the sustainability of DRWHS; highly seasonal rainfall and small roof sizes (averaging 70 m2) resulted in households unable to meet annual water needs. Increasing roof sizes and providing water treatment could ensure DRWHS sustainability in the studied community.

Download Full-text

DEVELOPING IMPROVED DRYLAND CROPPING SYSTEMS FOR MAIZE IN SEMI-ARID TANZANIA. PART II. USE OF A MODEL TO EXTRAPOLATE AND ADD VALUE TO EXPERIMENTAL RESULTS

Experimental Agriculture ◽

10.1017/s0014479703001297 ◽

2003 ◽

Vol 39 (3) ◽

pp. 293-306 ◽

Cited By ~ 4

Author(s):

J. W. GOWING ◽

M. D. B. YOUNG ◽

N. HATIBU ◽

H. F. MAHOO ◽

F. RWEHUMBIZA ◽

...

Keyword(s):

Crop Production ◽

Rainwater Harvesting ◽

Cropping Systems ◽

Objective Assessment ◽

Experimental Results ◽

Rainfall Regime ◽

Drought Risk ◽

Target Area ◽

Harvesting Systems ◽

Semi Arid

Dryland agriculture is critically important to food security and rural livelihoods in Tanzania, but crop production is seriously constrained throughout the semi-arid lowlands by the rainfall regime. A major challenge is to develop improved cropping systems to alleviate the moisture constraint. Experimental evidence indicates that adoption of rainwater harvesting systems can bring benefits, but the restricted spatial and temporal extent of the experimental work leads to difficulties in extrapolation. This paper shows how the PARCHED-THIRST model can add value to the experimental results and provide important insights into their transferability. The model is seen as an aid to researchers, planners and extensionists in interpreting experimental results and designing locally appropriate interventions. Simulation based on 30 years of daily meteorological data provides an opportunity for temporal extrapolation. The long-term simulation allows an objective assessment of the risks and benefits associated with alternative rainwater harvesting systems. Simulation for different soils and modified rainfall regimes permits objective analysis of spatial transferability of experimental results to any other site for which rainwater harvesting interventions might be considered. It is shown that macrocatchment rainwater harvesting reduces drought risk within the target area, but may bring a serious risk of erosion due to excessively high flow rates. The overall assessment of the twin-track approach (experimentation+simulation) is that rainwater harvesting has potential for increasing productivity and sustainability of maize cropping systems in semi-arid Tanzania provided that the innovations are properly matched to the site-specific environmental conditions.

Download Full-text